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Valence‐Band Properties of Bi 2 Te 3 from Galvanomagnetic Measurements
Author(s) -
Sologub V. V.,
Goletskaya A. D.,
Lang I. G.,
Pavlov S. T.
Publication year - 1973
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220580205
Subject(s) - condensed matter physics , valence band , magnetic field , valence (chemistry) , physics , chemistry , band gap , quantum mechanics
Abstract Galvanomagnetic effects in Bi 2 Te 3 are investigated in magnetic fields up to 38 kOe at 1.6 and 4.2 °K on six single‐crystal samples with hole concentrations between 1.4 × 10 18 and 2.4 × 10 19 cm −3 . A proper arbitrary‐field theory is developed for highly degenerated p‐ or n‐type Bi 2 Te 3 on the basis of a six‐ellipsoid Drabble‐Wolfe model (DM). In accordance with Shubnikov‐de Haas oscillations, the experimental data in the concentration range over 3 to 4 × 10 18 cm −3 exhibit considerable deviations from a simple DW behaviour. Using an extension of the galvanomagnetic theory to the case of two six‐ellipsoidal subbands, a good fit with the data is obtained, which do not fit to the DW description. However, a test two‐band estimate in terms of the calculated concentrations and density of states masses results in a too narrow energy gap between the subbands in the 7.1 × 10 18 cm −3 sample (an order of magnitude lower than the chemical potential). The upper subband should populated at hole concentrations of the order 10 17 cm −3 , in contradiction to the threshold concentration of 3 to 4 × 10 18 cm −3 , which has been obtained in the high‐field analysis of the whole series of samples investigated.